biomarkerguided

Biomarkerguided, or biomarker-guided therapy, is a clinical approach that uses measurable biological indicators to inform diagnosis, prognosis, and treatment decisions. By applying validated assays, healthcare providers classify patients and tailor interventions to maximize benefit and minimize harm.

Biomarkers can be predictive, indicating likely benefit from a therapy; prognostic, signaling disease outcome; or diagnostic, helping define a condition. Tests may be tissue-based, such as sequencing or immunohistochemistry, or noninvasive, such as circulating tumor DNA or protein biomarkers. Biomarker findings are often integrated with clinical factors in decision-making.

Applications are widespread but most prominent in oncology. Examples include HER2 status guiding trastuzumab in breast cancer, EGFR mutations guiding tyrosine kinase inhibitors in non-small cell lung cancer, BRCA1/2 status guiding PARP inhibitors, and PD-L1 expression or tumor mutational burden informing immune checkpoint inhibitors. Pharmacogenomic markers, such as TPMT testing for azathioprine dosing, illustrate non-oncologic uses.

Implementation relies on validated companion diagnostics and regulatory approvals, with trial designs like enrichment, basket, and umbrella trials. Advances in liquid biopsy and dynamic monitoring enable ongoing adaptation of therapy as biomarkers change.

Benefits include improved efficacy and reduced toxicity, but challenges remain, including assay standardization, access disparities, cost, and tumor heterogeneity. Careful validation and equitable implementation are essential to realizing the promise of biomarker-guided care. See also companion diagnostic, precision medicine, pharmacogenomics, and liquid biopsy.